1. Related Application
The present invention is an improvement over U.S. application Ser. No. 07/136,824 filed Dec. 22, 1987, and now U.S. Pat. No. 4,878,567, entitled "Brake/Locking Differential" which is assigned to the same assignee.
2. Field of the Invention
The present invention relates to a brake/lock differential for a hydrostatic transaxle drive assembly in which each wheel has a separate hydraulic drive motor. The brake/lock differential is used to provide power to both wheels if one wheel loses traction as well as to apply brake pressure to both wheels at the same time. The invention is more particularly related to a high torque brake/lock differential for heavy duty all terrain vehicles (ATV) and lawn and garden tractors.
3. Description of the Prior Art
The brake/locking differential described in the above identified application provides the brake/lock function by the engagement of a single drive plate mounted on one shaft with a clutch plate or brake plate mounted on the other shaft. The differential being selectively operated in the drive mode by connecting the drive plate to the clutch plate so the shafts operate at the same speeds or in the brake mode by connecting the drive plate to the brake plate to stop the rotation of the shafts. As the size of lawn and garden tractors has increased, the single brake plate and single clutch plate arrangement does not have the capability of providing sufficient frictional torque to handle this higher torque requirement without an increase in package size or thrust loads, both options of which are expensive.